Electronic emission device



Patented Sept. 3,, i942 STATES PATENT OFFICE ELECTRONIC ElHISSION DEVICE David Applebaum, Los Angeles, Calif.

Application April 4, 1939, Serial No. 265,906

2 Claims. (Cl. 179-171) This invention relates to an electronic emission device, utilizing a flow of electrons between electrodes. This application is a continuation in part of an application entitled Electronic emission device" filed October 30, 1936, in the name of David Applebaum, Serial No.108,386.

It is now common practice to provide a plurality of electrodes in an evacuated vessel, one of them serving as a cathode or source of electrons, and another serving as an anode to which the electrons are attached. The cathode may be of the heated type, such as a filament; and the anode may be maintained at a positive potential with respect thereto. The control of the electron stream is usually accomplished by the aid of a grid or control electrodes.

In such prior devices, the output power has been limited. It is one of the objects of this invention to make it possible to obtain an ampliiied output poweroi the order of a kilowatt. This is accomplished by the aid of a novel tube structure, in which high potential differences are utilized between certain of the electrodes, for producing an increased intensity of electrons.

It is possible to utilize the tube for other than amplifier purposes, such as for detection, as well as for modulation, or as-a combined amplifier and detector.

It is another object of this invention to provide a vacuum tube device that is capable of delivering a large output although it is compact and simple in structure. This result is due in part to the provision ofa plurality of electric fields arranged to act upon a common electronic stream along different portions of the length of the stream.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the drawing accompanying and forming part of the present specifization. This form will now be described in de- ;ail, illustrating the general principles of the mvention; but it is to be understood that this ietailedgdescription is not to be taken in a limitng serise; since the scope of this invention is nest defined by the appended claims.

Referring to the drawing, the single figure is i diagram of one form of the invention.

The electronic .emission device includes an evacuated envelope l, which may conveniently we considered as providing a pair of sections 2| md 22. Within this evacuated vessel are two envelope. One set of electrodes, corresponding to the input side of the device, is arranged in section 2| of the envelope 5 and includes a source of electrons 2, such as a filamentary cathode, a control electrode or grid 3, and an anode d, forming in efiect a conventional triode. The source of electrons 3 may be heated by a passage of electric current from a battery 5, and the anode l may be maintained at a positive potential with respect to the cathode 2 as by the aid of a battery 5. A resistance 7 is bridged across the filament 2 to form a potentiometer connection in the circuit from the anode to the cathode 2. The anode 4 serves to draw the electrons in a stream 8 from the cathode 2, and past the control grid 3, the source of direct current potential 6 having a sufiiciently high potential to accomplish this result. It may be of the order of one thousand or two thousand volts.

Another set of electrodes is arranged in the other section 22 of the envelope 4 and includes a tubular electrode 9 and an electron receiving electrode or anti-cathode it. The electrode 9 may be in the form of a metallic tube defining a narrow canal through which the stream 8 passes; the anti-cathode I ll may be maintained at a very high potential with respect to the electrode 9 as by the aid of a source of direct current energy II. This source may serve to provide a very high potential difierence of the order of thousands of volts.

It is apparent that the electrons flow from the source 2 toward the anode 4, in an amount depending on the action of the control grid 3. Some of the electrons will be attracted to the anode 4, from which they return to the cathode 2. other electrons will be carried past the anode A and into the electrode 9, due to their momentum and to the fact that electrode 9 is maintained positive with respect to the anode 4. These electrons then travel through the electrode 9 to the anti-cathode Ill, from which they return through the load circuit to the cathode 2. The electrode 9 serves to shield electro-steticaliy, the section 2| of envelope i from section 22 of the envelope and isolates the electro-static field of the anticathode it, from elements 2, 3 and A of the triode, whereby the effect oi. the potential of the'anticathode ill upon the electrons in the triode section of the tube is materially reduced. Accord= ingly adjacent the cathode or source of electrons 2 the electrons traverse one electric field, and between the electrodes 9 and in they traverse another field. The high electro-static stress ;ets of electrodes, one set in each section of the is between electrodes 9 and in section 22, so

a source of impulses l2, which may be a microphone circuit. The output circuit connecting the electrodes 2 and ID will then carry a current corresponding to the amplification which may be or such an order as to correspond to a considerable power output. In the present instance, a grid biasing battery 20 is indicated connected in the input circuit of the device.

By appropriate connections this system may be utilized as a detector, or it may also be used for modulating the oscillations produced in an oscillator system.

What is claimed is:

1. In an electronic emission device, an evacuated envelope forming a pair oi! sections, a triode in one section including an electron emitter, an anode for drawing electrons from the emitter and a control grid for modulating the electron stream, means for impressing a potential difference between said anode and said emitter, means forming an anti-cathode in the other section for receiving at least a portion or the electron stream, means for impressing a high potential on said means with respect to the emitter, a tubular electrode within said other section and having a narrow opening through which said electron stream is adapted to pass, and means for maintaining said electrode at an intermediate potential with respect to the anticathode and the anode, said electrode forming an electro-static shield in said other sections and thereby preventing the formation of an intense field in said first section by the potential on said anticathode.

2. In an electronic emission device, an evacuated envelope forming a pair or sections, means, including a control grid and a cathode, forming a triode in one of said sections for emitting a modulated stream of electrons, means providing an operating potential !or said triode, means forming-an anticathode in the other 01 said sections for receiving at least a portion of said stream, means maintainin said anticathode at a high potential with respect to said triode, a tubular electrode in said other sections, and

means maintaining said electrode at a potential intermediate that of the anticathode and the triode, said tubular electrode having an opening small compared to its length and serving as a directing and accelerating electrode for the electron stream, as well as an electrostatic shield to prevent the potential of said anticathode aftesting the operation of the triode.

DAVID APPLEBAUM. 

